According to the M&A investment agencies, the value of Kamagames is at around $500 million.
So the answer to the question "why are they making a token sale?" is just a one (I found it in WP):
"The company will use the Token Sale model to further expand its network of clients and to continue to deliver first-class gaming experiences and services worldwide"
Very well said. Even KAMAGAMES reached the highest growth they wouldnt stop to expand its network. They wanted to be the number 1 social casino games.